Princess Anne visited a convalescent home for retired railway workers in Dawlish as part of a whistle-stop tour of Devon and Cornwall.
She toured Bridge House, the last remaining facility of a network created around the country more than a century ago, and officially opened a new set of rented apartments.
The princess met staff, local dignitaries, young children and chatted individually to each one of the two dozen guests in residence.
She walked around the four-acre garden estate yesterday, wearing a terracotta-coloured overcoat, calf-length boots and gloves, with sporty white-framed Team GB sunglasses to shield her from the bright sunshine.
She was greeted with a single flower by schoolboy Jamie Ray Fenton, four, from Gatehouse primary school, before joking to onlookers about the new "waterfall" in the town – a burst water main which was drenching locals in a nearby road.
Inside the main hall, which boasts a bar and piano player, she unveiled a plaque to officially open Waterside Apartments, a refurbished building now containing nine flats for rent to the over-55s, which was completed last month.
To the assembled crowd she said the historic site had "evolved" and was still "playing a modern role", then, in reference to the warm, sunny day, added: "If it's always like this in Dawlish I can see why it's so popular – you should put your names down."
The elderly residents were delighted and excited by the unexpected royal appearance.
Charlie Hammond, a retired driver, aged 85, from Oswestry, who was staying with his wife Rose, said: "We didn't know she was coming until we got down here – she seemed very ordinary and down to earth, our kind of lady."